The present invention relates to a process and an apparatus for opening folded printed products, and more particularly the present invention relates to a process and an apparatus for opening folded printed products which uses a stabbing element in conjunction with a gripper device to open printed products.
U.S. Pat. No. 4,489,930 and the corresponding EP A-0 095 603 teach an arrangement wherein folded printed products, which are folded in an off-centered manner, are held by transport clips such that the fold runs transversely to the conveying direction and conveyed hanging obliquely to the rear. Underneath this conveying device there is an opening unit having an endless belt which is driven at the conveying speed of the conveying device. Grippers are arranged on the conveying belt such that they have the same spacing as the transport clips. The active side of the belt runs parallel to the conveying direction. The belt is preceded by a supporting member, in order to support the printed products in their trailing end region, opposite the fold. Following on from the belt (seen in the conveying direction) is a small acceleration belt. The small acceleration belt circulates at a higher speed than the conveying speed of the conveying device and the belt. In this off-center arrangement, the printed products have an upper-lying first product part which projects beyond a shorter, lower-lying second product part. This border section of each printed product is seized by a gripper of the opening unit and firmly clamped between itself and the belt. The lower-lying second product part is then moved away from the faster-running acceleration belt. This results in a bulging of the held first product part, and the printed product is thus opened. A saddle-shaped rest of a processing device then runs into each of the opened printed products between the product parts, which have been lifted off of each other. After release of the printed products by the transport clips, the products fall astride onto the rests. With this known process and with this known apparatus it is only possible to open off-centered folded printed products which are transported with a trailing end region and an upper-lying border section. Reliable opening of the printed products is only possible if the paper has a low intrinsic rigidity and the lower-lying product part has a certain weight. Moreover, in order to reliably open the printed products, the product parts cannot adhere to each other, for example due to electrostatic charging.
It is therefore an object of the present invention to develop the generic process and to provide a corresponding apparatus such that opening is independent of the position and the nature of the printed products and is reliably ensured.